What does it take to neck down 300 RUM brass to 7MM RUM

[dwm]

Can I just run the 300RUM brass through my 7MM RUM dies and be done?

How much will the neck thickness increase?

My 7MM RUM can't use factory brass so I will have to turn the necks anyway. (tight neck chamber)

Doug

 

[Boyd Heaton]

Yes you can...............No way of telling.........And yes you will........

 

[speedbump]

Agreed. I've done hundreds. Run them through a full length sizing die & fireform.

 

[Brent]

Doug,
Size, turn, shoot, and enjoy how easy that was!

I doubt you'll see a substantial increase. Going from 338 to 30, I don't. But I too must turn them anyway.